Adenoviral vector-mediated GDNF gene therapy in a rodent lesion model of late stage Parkinson's disease

A recombinant adenoviral vector encoding the human glial cell line-derived neurotrophic factor (GDNF) gene (Ad-GDNF) was used to express the neurotrophic factor GDNF in the unilaterally 6-hydroxydopamine (6-OHDA) denervated substantia nigra (SN) of adult rats ten weeks following the 6-OHDA injection. 6-OHDA lesions significantly increased apomorphine-induced (contralateral) rotations and reduced striatal and nigral dopamine (DA) levels by 99% and 70%, respectively. Ad-GDNF significantly (P < 0.01) decreased (by 30-40%) apomorphine-induced rotations in lesioned rats for up to two weeks following a single injection. Locomotor activity, assessed 7 days following the Ad-GDNF injection, was also significantly (P < 0.05) increased (by 300-400%). Two weeks after the Ad-GDNF injection, locomotor activity was still significantly increased compared to the Ad-beta-gal-injected 6-OHDA lesioned (control) group. Additionally, in Ad-GDNF-injected rats, there was a significant decrease (10-13%) in weight gain which persisted for approximately two weeks following the injection. Consistent with the behavioral changes, levels of DA and the metabolite dihydroxyphenylacetic acid (DOPAC) were elevated (by 98% and 65%, respectively) in the SN, but not the striatum of Ad-GDNF-injected rats. Overall, a single Ad-GDNF injection had significant effects for 2-3 weeks following administration. These results suggest that virally delivered GDNF promotes the recovery of nigral dopaminergic tone (i.e.: increased DA and DOPAC levels) and improves behavioral performance (i.e.: decreased rotations, increased locomotion) in rodents with extensive nigrostriatal dopaminergic denervation. Moreover, our results suggest that viral delivery of trophic factors may be used eventually to treat neurodegenerative diseases such as Parkinson's disease.

ret receptor tyrosine kinase immunoreactivity is altered in glial cell line-derived neurotrophic factor-responsive neurons following lesions of the nigrostriatal and septohippocampal pathways

Glial cell line-derived neurotrophic factor was initially identified as a survival factor for developing midbrain dopamine neurons (for reviews, see Refs 17 and 19). Subsequent studies have demonstrated a more wide-spread role for glial cell line-derived neurotrophic factor in the developing and adult CNS. In the adult rat brain, for instance, prior administration of glial cell line-derived neurotrophic factor protects nigrostriatal dopamine neurons from 6-hydroxydopamine-induced damage. When given several weeks after 6-hydroxydopamine injection, glial cell line-derived neurotrophic factor also restores the function of these neurons. Glial cell line-derived neurotrophic factor attenuates excitotoxin-induced cell death in the striatum and hippocampal formation and protective effects of glial cell line-derived neurotrophic factor following axotomy have been reported for spinal motor neurons and basal forebrain cholinergic neurons. These findings suggest that glial cell line-derived neurotrophic factor may be a protective/restorative agent for a diverse population of neurons and imply that it may be a useful therapeutic tool for a variety of neurodegenerative diseases including Parkinson's, Huntington's and Alzheimer's diseases. The potential receptor mediating the pleiotropic effects of glial cell line-derived neurotrophic factor has been characterized only recently as a novel glycosyl-phosphatidylinositol-linked protein, GDNFR-alpha. Because GDNFR-alpha is a cell surface receptor, an additional protein(s) was thought to be involved in the glial cell line-derived neurotrophic factor signalling cascade. The identity of the likely candidate, ret, was inferred initially from indirect evidence. Not only were there remarkable similarities in the distribution of glial cell line-derived neurotrophic factor and the proto-oncogene ret in the developing rat and mouse brain, but also in the phenotype of glial cell line-derived neurotrophic factor knockout mice and mice with ret mutations. Mice with either mutation exhibited pronounced renal and enteric abnormalities, implicating the receptor tyrosine kinase protein product of the ret proto-oncogene as the glial cell line-derived neurotrophic factor signalling protein. More conclusive evidence showing that activation of GDNFR-alpha by glial cell line-derived neurotrophic factor induces phosphorylation of ret has confirmed ret as a signalling protein for glial cell line-derived neurotrophic factor. Preliminary results showing that 6-hydroxydopamine lesions of the substantia nigra markedly reduced ret messenger RNA expression, established its localization to presumably glial cell line-derived neurotrophic factor-responsive dopamine neurons in the nigrostriatal pathway. In contrast, it is not clear whether other glial cell line-derived neurotrophic factor-responsive neurons in the CNS, such as the basal forebrain cholinergic neurons and striatal neurons, also express ret, nor is it evident whether levels of the protein are regulated by disruption of the respective pathways. The present study shows that dense networks of ret immunoreactivity are distributed throughout the nigrostriatal pathway, with lower densities of staining in other brain regions, including the septohippocampal pathway. Following extensive unilateral 6-hydroxydopamine lesions of the medial forebrain bundle, ret immunoreactivity in the substantia nigra and striatum was reduced significantly, to a similar extent as tyrosine hydroxylase immunoreactivity. In contrast, excitotoxic lesions of the striatum, achieved by intrastriatal quinolinic acid injections, resulted in increased ret staining in this brain region. In addition, marked decrements in septal ret immunoreactivity were consequent to complete transections of the fimbria-fornix.

Characteristics of coronary artery disease and lipoprotein abnormalities in patients with heterozygous familial hypercholesterolemia associated with diabetes mellitus or impaired glucose tolerance

Familial hypercholesterolemia (FH) is a genetic disorder characterized by high levels of serum low density lipoprotein (LDL) cholesterol and premature coronary atherosclerosis. In order to elucidate the influence of abnormal glucose metabolism on the development of coronary artery disease (CAD) in FH patients, we examined the prevalence of CAD and characteristics of lipoprotein abnormalities in patients with heterozygous FH who were accompanied by diabetes mellitus (DM) or impaired glucose tolerance (IGT). The subjects of the present study were 150 patients with heterozygous FH, all over 40 years of age. Oral glucose tolerance tests demonstrated that 15 patients had DM and 27 had IGT. The combination of DM or IGT with FH was associated with a further increase in the prevalence of CAD (DM:IGT:normal glucose tolerance (N), 87:59:43%). Furthermore, the prevalence of the stenoses in the distal coronary arteries was significantly higher in the DM group than in the N group, while there was no significant difference in the prevalence of proximal and middle lesions. Serum triglyceride levels were significantly higher in the DM and IGT groups than in the N group (P < 0.01, DM versus N group; P < 0.01, IGT versus N group), while total cholesterol levels were not significantly different. When lipoproteins were analyzed by polyacrylamide gel electrophoresis, the frequency of midband appearance, which implies an increase in remnant lipoproteins, was significantly higher in the DM and IGT groups than in the N group (DM:IGT:N, 87:72:29%, P < 0.01, DM versus N group; P < 0.01, IGT versus N group). Ultracentrifugation analysis of lipoproteins revealed that intermediate density lipoprotein cholesterol was increased in DM and IGT groups compared with the N group. These data suggest that abnormal glucose metabolism may accelerate the development of CAD in FH patients due to an increase in atherogenic remnant lipoproteins in addition to high concentration of LDL. Special attention should be paid in the treatment of FH patients with impaired glucose metabolism, to avoid the advancement of coronary atherosclerosis.

[Clinical significance of p21H-ras expression and H-ras codon 12 mutation in squamous intraepithelial lesion (SIL) and carcinoma of uterine cervix]

OBJECTIVE

To study the clinical significance of p21 H-ras expression and H-ras codon 12 mutation in SIL and cervical carcinoma.

METHODS

p21 H-ras expression and H-ras codon 12 mutation was detected in the same paraffin embedded tissues of 171 cases of cervical carcinoma, 68 cases of SIL, and 29 cases of chronic cervicitis, by using immunohistochemical and PCR-RFLP techniques.

RESULTS

(1)p21 H-ras was over-expressed in 25.0% of the cases with low-grade SIL but in most of them the immunohistochemical staining was not strong (score < 3). p21 H-ras over-expression was present in 64. 6% of the cases with high-grade SIL and in 35.4% of them, the staining was strong (score = 3). Even higher frequency of p21 H-ras over-expression was seen in cases with cervical carcinoma (66.1%) and in about one-half (49.7%) the staining was strong. (2) H-ras codon 12 mutation was only detected in stages II and III cervical carcinoma, with frequency rate of 27.0% and 52.5% respectively. The five-year survival rate of patients with H-ras codon 12 mutation (20.3%) was significantly lower than that without mutation (79.7%). Besides, there was a correlation between lymph node metastasis and H-ras codon 12 mutation.

CONCLUSION

p21 H-ras expression is helpful for early detection of cervical carcinoma. Aggressive biological behavior of cervical carcinoma is significantly increased once the H-ras codon 12 mutation occurs. H-ras codon 12 mutation is helpful to judge prognosis of cervical carcinoma.

Glial cell line-derived neurotrophic factor attenuates behavioural deficits and regulates nigrostriatal dopaminergic and peptidergic markers in 6-hydroxydopamine-lesioned adult rats: comparison of intraventricular and intranigral delivery

The effects of intranigrally- or intraventricularly-administered glial cell line-derived neurotrophic factor were tested on low dose (0.05 mg/kg) apomorphine-induced rotations and tyrosine hydroxylase activity in the substantia nigra and striatum of stable 6-hydroxydopamine-lesioned rats. In addition, we determined if 6-hydroxydopamine lesions in the absence or presence of treatment affected neuropeptide (substance P, met-enkephalin, dynorphin) content in the striatum. Glial cell line-derived neurotrophic factor, when administered intranigrally, prevented apomorphine-induced rotational behaviour for 11 weeks following a single injection. In comparison, intraventricularly-administered glial cell line-derived neurotrophic factor produced a transient reduction in rotational behaviour that lasted for two to three weeks following a single injection. We also show that rotational behaviour is reduced following each subsequent intraventricular injection of glial cell line-derived neurotrophic factor given every six weeks, a time-point when baseline rotation deficits were re-established. Intranigrally- or intraventricularly-administered glial cell line-derived neurotrophic factor significantly reduced weight gain in all 6-hydroxydopamine-lesioned rats in this study. Following behavioural analysis where a confirmed improvement of behaviour was established, tissues were dissected for neurochemical analysis. In lesioned rats with intranigral injections of administered glial cell line-derived neurotrophic factor, significant increases of nigral, but not striatal tyrosine hydroxylase activity were measured. Additionally, 6-hydroxydopamine lesions significantly increased striatal dynorphin (61-139%) and met-enkephalin (81-139%), but not substance P levels. In these rats, intranigrally-administered glial cell line-derived neurotrophic factor injections reversed lesion-induced increases in nigral dynorphin A levels and increased nigral dopamine levels, but did not alter nigral met-enkephalin or substance P levels nor striatal dopamine levels. In lesioned rats with intraventricular injections of glial cell line-derived neurotrophic factor, tyrosine hydroxylase ispilateral to the lesion was increased in the substantia nigra, but not in the striatum. Intraventricularly-administered glial cell line-derived neurotrophic factor did not reverse lesion-induced increases in nigral dynorphin A or met-enkephalin levels nor did glial cell line-derived neurotrophic factor affect substance P levels in the striatum. These results suggest that in an animal model of Parkinson's disease, the neurotrophic factor glial cell line-derived neurotrophic factor reverses behavioural consequences of 6-hydroxydopamine administration, an effect that may involve both dopaminergic and peptidergic neurotransmission.

Glial cell line-derived neurotrophic factor induces the dopaminergic and cholinergic phenotype and increases locomotor activity in aged Fischer 344 rats

Glial cell line-derived neurotrophic factor has been shown to affect dopaminergic and cholinergic neuron markers and functions in young rats. However, it is not known if the response to exogenous glial cell line-derived neurotrophic factor is augmented during normal aging. Thus, the effects of chronic intraventricular infusions of glial cell line-derived neurotrophic factor were determined in young adult (three-months-old) and aged (24-months-old) Fischer 344 (F344) male rats. The effects of glial cell line-derived neurotrophic factor were compared to the effects of the neurotrophin nerve growth factor. Growth factors were administered at a dose of 10 mg/day for 14 days. Locomotor activity and weight changes were also examined in all rats. Aged F344 rats showed significantly reduced (by 75-80%) locomotor activity compared to young rats. In glial cell line-derived neurotrophic factor-treated aged and young rats there was significantly increased (242% and 149%, respectively) locomotor activity measured at seven days. There was also a significant increase in locomotor activity measured 14 days after the start of infusion. Both glial cell line-derived neurotrophic factor and nerve growth factor reduced weight gain by 10% in young and old F344 rats. Two weeks following the start of nerve growth factor or glial cell line-derived neurotrophic factor administration the brains were used for neurochemical analyses. Glial cell line-derived neurotrophic factor significantly increased tyrosine hydroxylase activity in the substantia nigra and striatum of aged rats and in the substantia nigra of young rats. Nerve growth factor treatment did not significantly affect tyrosine hydroxylase activity. However, glial cell line-derived neurotrophic factor and nerve growth factor increased choline acetyltransferase activity in the septum, hippocampus, striatum and cortex of aged rats and in the hippocampus and striatum of young rats to a comparable degree. These findings indicate that specific dopaminergic and cholinergic neuron populations remain responsive to glial cell line-derived neurotrophic factor during the life span of the rat and may be involved in maintaining phenotypic expression within multiple neuronal populations. Additionally, the glial cell line-derived neurotrophic factor-induced up-regulation of brain neurotransmitter systems may be responsible for increased locomotor activity in F344 rats.

Glial cell line-derived neurotrophic factor: a novel therapeutic approach to treat motor dysfunction in Parkinson's disease

The discovery of the novel neurotrophic factor glial cell-line derived neurotrophic factor (GDNF) in 1993 sparked the interest of basic neuroscientists and clinicians alike. Since that time, many aspects of GDNF's physiology and pharmacology have been studied in great detail. GDNF has been shown to be a potent survival factor for dopaminergic neurons during development. GDNF also has been shown to be a survival factor and neurotrophic factor for nigrostriatal dopaminergic neurons in the adult. The factor also reverses behavioral deficits in a rodent and primate model of Parkinson's disease. The overall goal will be to discuss the pharmacology of GDNF in the context of a potential therapeutic use to treat Parkinson's disease. Thus, the following report presents a comprehensive review of the development of GDNF's pharmacology and evidence which supports the clinical use of GDNF to treat dopaminergic deficits and motor dysfunctions in Parkinson's disease.

Glial cell line-derived neurotrophic factor: distribution and pharmacology in the rat following a bolus intraventricular injection

Glial cell line-derived neurotrophic factor (GDNF) has been shown to increase dopaminergic parameters in vitro and in vivo and can reduce parkinsonian behaviors in animal models of the disease. This study determined the potential of the lateral ventricle as an administration route for GDNF by examining the distribution and neurochemical consequences of a single intraventricular injection. Autoradiographic analysis showed that intraventricularly administered [125I]GDNF was distributed throughout the ventricular system at 1 and 24 h following injection. The cerebral cortex, septum, diagonal band, fimbria, striatum, hippocampus, hypothalamus, substantia nigra/ventral tegmental area, and cerebellum were also labeled. At 7 days, there was still labeling throughout the ventricular system, hypothalamus, substantia nigra, and cerebellum. Twenty-four hours following an intrastriatal injection of [125I]GDNF, label was observed in the substantia nigra/ventral tegmental area, demonstrating retrograde transport. The neurochemical effects of intraventricularly administered GDNF (0.1-100 micrograms) at 7 days post injection were also examined. GDNF significantly increased striatal (approximately 28%) and nigral (up to 40%) dopamine, as well as regulated the dopamine metabolites homovanillic acid and dihydroxyphenylacetic acid. Dopamine levels were unchanged in the frontal cortex. Dopamine content was significantly increased in the hypothalamus (up to 35%), an increase which may contribute to the inhibition of weight gain seen after administration of GDNF. Additionally, dopamine turnover was decreased or unchanged across the brain regions analyzed, which may indicate that in unlesioned rats, intraventricularly administered GDNF stimulates the synthesis and storage of dopamine. This study shows that intraventricularly injected GDNF can access basal ganglia structures, most notably the midbrain dopamine cell body region, and remains present in this area for at least 7 days following a single administration. GDNF differentially increases dopaminergic tone within a variety of brain structures, including the nigrostriatal pathway. These data support the potential effectiveness of intraventricular administered GDNF as a treatment for Parkinson's disease.

Enhanced delivery of [125I]glial cell line-derived neurotrophic factor to the rat CNS following osmotic blood-brain barrier modification

Subsequent to osmotic (mannitol-induced) blood-brain barrier (BBB) opening, [125I]glial cell line-derived neurotrophic factor (GDNF) was detected throughout the ventricular system, associated with the ependymal cell layer and extracellular matrix and to some extent penetrated into the cerebral cortex, subcortical gray matter, substantia nigra, septum, eye and optic nerve at 1 and 24 h following an intracarotid administration. Our study indicates that osmotic opening of the BBB allows for extensive distribution of GDNF throughout the central nervous system (CNS).

Pharmacological characterization of glial cell line-derived neurotrophic factor (GDNF): implications for GDNF as a therapeutic molecule for treating neurodegenerative diseases

This review presents a comprehensive survey of the recently described pharmacological activities of glial cell line-derived neurotrophic factor on the central nervous system.

[A study on DNA content and cell cycle phase analysis in endometrial carcinoma]

OBJECTIVE

To study the prognostic value of DNA content, cell cycle phase in endometrial carcinoma.

METHODS

DNA content and cell cycle phase analysis were performed on 100 paraffin-embedded archival specimens from 103 cases of endometrial carcinoma using flow cytometry.

RESULTS

Aneuploidy was found in 71.0% of specimens. The aneuploidy rate in specimens from grade III, deep myometrial invasion and stage III, IV was significantly higher than that in specimens from grade I, nonmyometrial invasion and stage I (P < 0.05 respectively). 5-year survival rate for patients with aneuploidy was 65.9% and for patients with diploidy was 87.6% (P < 0.01). High S-phase fraction (SPF) was associated with high grade, deep myometrial invasion and advanced stage. The mean SPF was 13.4% in the living group and 17% in the dead group. The 5-year survival rate for patients with SPF > 17% was 50.4% and for patients with SPF < 17% was 79.1% (P < 0.01). SPF and stage were the most important prognostic factors in endometrial carcinoma by Cox's proportional hazards model.

CONCLUSIONS

DNA ploidy and SPF were found to be of important prognostic indicators in endometrial carcinoma.

Efficient and sustained transgene expression in mature rat oligodendrocytes in primary culture

In order to evaluate the characteristics and efficiency of gene transfer in primary cultures of oligodendrocytes, four different techniques including particle bombardment (Accell gene gun), cationic liposome-mediated transfection (lipofection), calcium phosphate co-precipitation and retroviral infection were compared using the LacZ and luciferase reporter genes. Highly purified postnatal adult rat oligodendrocytes were obtained by sequential immunopanning, plated in culture, and transfected using various reporter and promoter genes. The most efficient expression of LacZ and luciferase genes was found with particle mediated gene delivery. The transgene expression level obtained with gene gun delivery was at least two- to 100-fold greater than three other tested gene transfer methods. Comparison of the relative strength of four viral and two cellular promoters in these primary oligodendrocytes cultures demonstrated that the CMV promoter was the strongest. Using a human growth hormone (hGH) reporter gene, a long-term transgene expression pattern in primary oligodendrocytes was demonstrated to be sustained in culture for the entire experimental period (4 weeks) after particle-mediated gene transfer. These results demonstrate that expression of a foreign gene can be effectively achieved in primary cultures of adult oligodendrocytes, especially by using the particle bombardment method. The results also suggest that the current ex vivo gene transfer system may be used to manipulate oligodendrocytes for future application in gene therapy studies.

[A study on expression of tumor suppressor gene p53 in endometrial carcinoma]

OBJECTIVE

To observe the relationship between suppressor gene p53 expression and endometrial carcinoma.

METHODS

Expression of p53 was studied by immunohistochemistry in paraffin sections from 23 normal endometrium, 44 endometrial hyperplasia and 103 endometrial carcinoma.

RESULTS

Immunohistochemical staining of p53 protein was negative in normal and hyperplastic endometrium but positive in 47.6% of endometrial carcinoma. In endometrial carcinoma, p53 over expression was significantly associated with histologic type, tumor grade, presence of vascular invasion and DNA aneuploidy. The survival rate of patients with p53 expression is significantly lower than that of patients without p53 expression (P < 0.001), the 5-year survival rate is 59.9% and 83.4% respectively. Patients with expression of mutant forms of the tumor suppressor gene p53 products had a 6.34-fold increased risk of death as compared with patients without p53 expression by Cox proportional hazards model.

CONCLUSIONS

Aberrant expression of p53 gene is indicative of aggressive biological behavior and poor survival in endometrial carcinoma.

Increased proportion of plasma apoB-48 to apoB-100 in non-insulin-dependent diabetic rats: contribution of enhanced apoB mRNA editing in the liver

To assess the alteration of apolipoprotein (apo) B mRNA editing in non-insulin-dependent diabetes mellitus (NIDDM), we measured plasma apoB-100 and apoB-48 levels and apoB mRNA editing efficiency in the liver and intestine from GK (Goto-Kakizaki) rats, a genetically NIDDM animal. Male GK rats and control littermates, aged 25 weeks, were used in this study. Ventromedial hypothalamus (VMH)-lesioned control rats were used as hyperinsulinemic models. VMH-lesioned GK rats (GK+VMH) were treated as an insulin-exhausted NIDDM model. Plasma cholesterol and triglyceride levels were increased in GK rats. Very low density lipoprotein (VLDL)-triglyceride and low density lipoprotein (LDL)-cholesterol concentrations were significantly higher in GK rats than in controls. The increase of VLDL-triglyceride was most marked in GK+VMH rats. Plasma apoB-48 levels, quantified by immunoblot, were increased in GK rats. However, apoB-100 levels were minimally elevated in GK rats. Therefore, the apoB-48/apoB-100 ratio was remarkably increased in GK rats. ApoB mRNA editing was analyzed by reverse transcriptase-polymerase chain reaction coupled with dideoxynucleotide chain termination assay. The ratio of apoB-48-type cDNA to apoB-100-type cDNA was significantly increased in the liver from GK rats compared with controls. Although the development of the VMH lesion increased plasma apoB-48 levels, it had no effect on the proportion of apoB-48-type to apoB-100-type cDNA in the liver from both GK and control littermates. ApoB mRNA in the intestine was almost totally edited (approximately 95%). Intestinal apoB-48/apoB-100 cDNA ratio showed no significant difference among the four groups. In conclusion, an enhanced apoB mRNA editing was indicated in the non-insulin-dependent diabetic rats, which might contribute to the increase of plasma apoB-48 levels.

Structure and function of selectable and non-selectable transgenes in maize after introduction by particle bombardment

Zea mays transformants produced by particle bombardment of embryogenic suspension culture cells of the genotype A188 x B73 and selected on kanamycin or bialaphos were characterized with respect to transgene integration, expression, and inheritance. Selection on bialaphos, mediated by the bar or pat genes, was more efficient than selection on kanamycin, mediated by the nptII gene. Most transformants contained multicopy, single locus, transgene insertion events. A transgene expression cassette was more likely to be rearranged if expression of that gene was not selected for during callus growth. Not all plants regenerated from calli representing single transformation events expressed the transgenes, and a non-selectable gene (uidA) was expressed in fewer plants than was the selectable transgene. Mendelian inheritance of transgenes consistent with transgene insertion at a single locus was observed for approximately two thirds of the transformants assessed. Transgene expression was typically, but not always, predictable in progeny plants--transgene silencing, as well as poor transgene transmission to progeny was observed in some plant lines in which the parent plants had expressed the transgene.

Induction of specific tolerance by intrathymic injection of recipient muscle cells transfected with donor class I major histocompatibility complex

Induction of tolerance to allogeneic MHC antigens has been a goal in the field of transplantation because it would reduce or eliminate the need for generalized immunosuppression. Although encouraging results have been obtained in experimental models by exposing recipient thymus to donor cells before transplantation, donor cells are not typically available at that time, and the donor antigens responsible for the effect are poorly defined. In the present study, thymic tolerance was demonstrated without using donor cells. Recipient thymus was injected before transplantation with autologous myoblasts and myotubes that were genetically modified to express allogeneic donor-type MHC class I antigen. Donor-specific unresponsiveness was induced to a completely MHC-disparate liver transplant and to a subsequent donor-type cardiac allograft, but not a third-party allograft. In vitro, recipient CTL demonstrated a 10-fold reduction in killing of donor cells, but not of third-party cells. Our results demonstrate: (1) that recipient muscle cells can be genetically engineered to induce donor-specific unresponsiveness when given intrathymically, and (2) transfected recipient cells expressing only donor MHC class I antigen can induce tolerance to a fully allogeneic donor.

Pharmacological enhancement of in vivo foreign gene expression in muscle

Intramuscular injection of naked plasmid DNA provides a means for gene transfer and expression in striated muscle. In this study, the effects of treating muscle with normal saline, etidocaine, mepivacaine, acetic anhydride, sodium bicarbonate, Notechis scutatus venom, cardiotoxin and bupivacaine before plasmid DNA injection on foreign gene expression were evaluated. Dose dependence, strain and species specificity, the time interval between pharmacological agent and plasmid DNA injection, the stability of gene expression and the fate of the injected plasmid DNA were studied using reporter gene expression, by histological examination and semi-quantitative polymerase chain reaction. Of the various agents tested, the best enhancement of foreign gene expression occurred in muscle treated with 0.75% bupivacaine five to seven days before plasmid DNA injection. Rat and mouse quadriceps muscle treated with 0.75% bupivacaine had levels of luciferase activity four- to 40-times greater than non-bupivacaine-treated muscle. Also, beta-galactosidase expressing myofibers were observed throughout the length of the muscle in samples treated with 0.75% bupivacaine before reporter gene injection. Muscle treated with 0.75% bupivacaine fully recovered from the degeneration caused by its injection with no long-term effects histologically. The heightened level of reporter gene expression persisted in 0.75% bupivacaine-treated muscle for one month, but decreased to that of non-bupivacaine-treated muscle by two months after plasmid DNA injection. Enhancement of foreign gene expression may be particularly advantageous in vaccination protocols employing intramuscular plasmid injection.

Familial hypercholesterolaemia-like syndrome with apolipoprotein E-7 associated with marked Achilles tendon xanthomas and coronary artery disease: a report of two cases

We observed two patients with hypercholesterolaemia and tendon xanthomas associated with apolipoprotein (apoE-7) E-7, a rare variant of the apoE isoforms. Both suffered from coronary artery disease and had undergone a coronary bypass operation. Their cholesterol levels were 268 and 310 mg dl-1, respectively. Both patients had marked xanthomas in the Achilles tendons. Both also suffered from diabetes. Although their clinical and laboratory findings were compatible with typical familial hypercholesterolaemia (FH), the analysis of low-density lipoprotein (LDL) receptors in cultured fibroblasts showed no abnormality of binding, internalization or degradation of 125I-LDL. Diabetic control with a low-calorie, low-fat diet led to the rapid reduction of serum cholesterol. Other family members of the patients with apoE-7, who were normoglycaemic, showed normal cholesterol levels and no xanthomas. These findings suggest that coexistent diabetes mellitus may induce overt hyperlipidaemia and accumulation of lipids in tissues in subjects with apoE7.

Secretion of immunoreactive beta-endorphin and GnRH by the pig uterus: effects of reproductive status and breed

Immunoreactive beta-endorphin (ir-BEND) and GnRH (ir-GnRH) have been identified in the pig uterus. The study reported here examined (i) possible biochemical differences between ir-BEND and ir-GnRH present in pig uterine fluids and standard synthetic peptides, and (ii) the secretory profiles of uterine ir-BEND and ir-GnRH during the oestrous cycle and early pregnancy for two breeds of pig, Large White and the highly prolific Chinese Meishan. Reverse phase (RP)-HPLC analysis of concentrated uterine fluids indicated that the majority of ir-BEND eluted with a hydrophobicity similar to that of synthetic BEND 1-31 (BEND) and alpha-N-acetylated BEND 1-31 (Nac-BEND), with a ratio of BEND to Nac-BEND of approximately 1.8:1. The RP-HPLC profiles of ir-GnRH demonstrated a major peak coeluting with synthetic GnRH, along with a minor peak eluting at the void volume. Total content of ir-BEND (pg per uterus) was affected by the interaction of breed with day (P < 0.001), but was independent of reproductive status. In Large White gilts, uterine fluid content of ir-BEND was higher (P < 0.05) on days 10 and 11 than on days 8, 12 and 14; however, in Meishan gilts, ir-BEND decreased from day 8 to days 10 and 11, and remained low on days 12 and 14. Compared to Meishan gilts, Large White gilts had higher ir-BEND concentrations on day 10 (P < 0.01), day 11 (P < 0.0001), day 12 (P < 0.01) and day 14 (P < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Marked reduction of acyl-CoA synthetase activity and mRNA in intra-abdominal visceral fat by physical exercise

Several reports have suggested that the reduction of intra-abdominal visceral fat after physical exercise is more prominent than that of subcutaneous fat. We compared some parameters in mesenteric and subcutaneous fats between sedentary and exercised rats (treadmill running; 10-20 m/min, 60 min/day, 7 days). Tissue weight and cell volume were decreased in mesenteric fat by the exercise. The exercise reduced activity and mRNA levels of acyl-CoA synthetase (ACS; 67 and 26% of those of the sedentary group, respectively), mRNA levels of lipoprotein lipase (LPL; 49% of those of the sedentary group), and GLUT-4 (38% of those of the sedentary group) in the mesenteric fat. In contrast, all of these parameters did not change significantly in the subcutaneous fat. Gastrocnemius muscle was heavier in exercised rats. ACS activity was elevated in the gastrocnemius muscle of the exercised rats (137% of those of sedentary group), although mRNA levels of ACS, LPL, and GLUT-4 did not change in the muscle by the exercise. These observations suggest that mesenteric fat may contribute to switching of distribution of plasma energy flux, including lipid and glucose, from fat tissue to muscle in physical exercise.

Immunoreactive gonadotropin-releasing hormone in porcine reproductive tissues

Studies were aimed to identify and characterize IR-GnRH in the porcine endometrium, ovary, oviduct, and compare that with GnRH of hypothalamic and placental origin. RP-HPLC profiles revealed that all tissue extracts contained three peaks of IR-GnRH. Extraction with radioiodinated 125I-GnRH also resulted in three similar peaks, indicating these two extra peaks as an extraction artifact. Radioreceptor assay showed endometrial and ovarian ultrafiltrates displaced binding of 125I-GnRH analog to pituitary membrane. Secretion of uterine IR-GnRH was increased in ovariectomized, progesterone-treated gilts, as compared to the control. Treatment with estradiol + progesterone in ovariectomized gilts further increase uterine secretion of IR-GnRH. These results demonstrate that IR-GnRH identified in the porcine reproductive tissues possesses hydrophobicity similar to those in hypothalamus and placenta; endometrial IR-GnRH binds to pituitary GnRH receptors; and uterine secretion of IR-GnRH is modulated by ovarian steroids.

Particle bombardment-mediated gene transfer and expression in rat brain tissues

We have previously demonstrated that the particle bombardment method for gene transfer (Accell) provides a new means for transfection of various cell types in culture. In this study we evaluate its application to rat brain systems. Using a luciferase (luc) gene as a reporter, we obtained high levels of transient gene expression in primary cultures of fetal brain tissue. Reduced but significant levels were also detected in adult brain primary cultures. Both neuron and glial cells were transfected using this technique. The transient gene expression level obtained with Accell was at least 100-fold higher than that obtained with three other gene transfer methods. The relative strengths of four cellular and seven viral promoters were also evaluated in these cultures. In vivo gene expression was studied using freshly excised and bombarded fetal brain tissues which were immediately transplanted into caudate or intracortical brain tissues of adult host animals. Assays showed that luciferase activity was present in transplants for up to two months following gene transfer. In vitro and in vivo expression of a rat tyrosine hydroxylase (TH) gene, a candidate gene for treatment of Parkinson's disease, was also detected in this rat brain system. Our results suggest that the particle bombardment gene transfer technology can be employed as an effective method for ex vivo gene transfer into brain tissues.

Long-term correction of rat model of Parkinson's disease by gene therapy

The implantation of cells genetically modified to express tyrosine hydroxylase has been proposed for the treatment of Parkinson's disease. Tyrosine hydroxylase converts tyrosine to L-DOPA and endogenous decarboxylase activity then converts L-DOPA to the neurotransmitter dopamine, which alleviates the symptoms of Parkinson's disease. Immortalized cells have been successfully used as intracerebral vehicles for transgene expression of tyrosine hydroxylase, but the tumorigenic potential of these cells prevents their application in humans. Intracerebral expression of this enzyme has also been achieved using primary cells like skin fibroblasts, but the ameliorating effect on a rat model for Parkinson's disease lasted for only a few weeks. We have found that co-transplantation of cultured myoblasts and myotubes enabled reporter genes to be expressed intracerebrally at high and stable levels. Here we show that the intracerebral transplantation of plasmid-transfected primary muscle cells can substantially reduce for the long-term the asymmetric rotational behaviour in the rat model.

Expression of naked plasmids by cultured myotubes and entry of plasmids into T tubules and caveolae of mammalian skeletal muscle

Plasmid DNA or artificial mRNA injected intramuscularly into skeletal muscle via a 27 g needle expressed transgenes at relatively efficient levels in skeletal myofibers and cardiac cells. In the present study, several approaches were used to determine the mechanism of cellular uptake. After exposure of naked plasmid DNA, primary rat muscle cells in vitro expressed transgenes to a much greater extent than other types of immortalized or primary cells. In vivo light microscope studies showed that intramuscularly injected plasmid DNA was distributed throughout the muscle and was able to diffuse through the extracellular matrix, cross the external lamina, and enter myofibers. Electron microscope studies showed that colloidal gold conjugated to plasmid DNA traversed the external lamina and entered T tubules and caveolae, while gold complexed with polylysine, polyethylene glycol or polyglutamate primarily remained outside of the myofibers. The results indicate that it is highly unlikely that the plasmid DNA enters the myofiber simply by the needle grossly disrupting the sarcolemma. In addition, transient membrane disruptions do not appear to be responsible for the uptake of DNA. Furthermore, no evidence for endocytosis could be found. The possible uptake of plasmid DNA by some type of cell membrane transporter, in particular via potocytosis, is discussed.

Long-term survival of autologous muscle grafts in rat brain

The ability of muscle to persist in the brain was explored. Pieces of rat quadriceps muscles were removed, minced and transplanted back into the same animal's cortex. Brains implanted with minced muscle consistently contained substantial grafts for at least 6 months. Histological, immunohistochemical, and electron microscopic examination indicated that the muscle grafts after 6 months contained healthy and well-differentiated myofibers. The long-term survival of muscle cells suggested that this technique will be useful for studies of brain and muscle and for the development of new therapeutic modalities.

Intracerebral transplants of primary muscle cells: a potential 'platform' for transgene expression in the brain

After the transplantation of rat primary muscle cells into the caudate or cortex of recipient rats, the muscle cells were able to persist for at least 6 months. Muscle cells transfected with expression plasmids prior to transplantation were able to express reporter genes in the brains for at least 2 months. These results suggest that muscle cells might be a useful 'platform' for transgene expression in the brain.

Marked enhancement of acyl-CoA synthetase activity and mRNA, paralleled to lipoprotein lipase mRNA, in adipose tissues of Zucker obese rats (fa/fa)

To clarify the role of acyl-CoA synthetase in development of obesity, the mRNA levels and activities were studied in Zucker fatty rats (fa/fa). In Zucker fatty rats compared with their lean littermates, marked enhancement of ACS were observed in adipose tissues. Obese/lean rats ratio of ACS activity and mRNA in abdominal subcutaneous fat (3.3- and 3.9-fold, respectively) were greater than in mesenteric fat (2.0- and 2.2-fold). The enhancement of ACS activity and mRNA in the liver of fatty rats (1.2- and 1.8-fold) were less than those in the adipose tissues. There were no enhancement of ACS activities and mRNA levels in heart tissue of the obese rats. LPL mRNA levels were also enhanced in adipose tissue of fatty rats and obese/lean ratio of LPL mRNA was also higher in abdominal subcutaneous fat than mesenteric fat (6.2- vs 3.1-fold). The larger obese/lean rats ratio of LPL and ACS parameters in abdominal subcutaneous fat than mesenteric fat may be related to the observation that the increase of subcutaneous fat weight was larger than that of mesenteric fat weight in fatty rats (21.1- vs 4.9-fold). Integrated enhancement of LPL and ACS gene expression in adipose tissue may play an important role in the development of obesity.

Persistence of plasmid DNA and expression in rat brain cells in vivo

The purpose of this study was to determine whether plasmid DNA is able to persist in nondividing or slowly dividing brain cells in vivo. A new cationic lipid formulation which contains 70 mol% of DOTMA (N[1-(2,3-dioleyloxy)propyl]-N, N, N-trimethylammonium) and 30 mol% of cholesterol was used to transfect reporter genes into fetal brain cells in culture that were then transplanted into adult host brains. Gene expression was localized both to glial and neuronal cells after transfection of fetal brain cells with pRSVLac-Z, the gene coding for Escherichia coli beta-galactosidase protein. After the transfection of pRSVL plasmid which contains the firefly luciferase gene into fetal brain cells that were transplanted, substantial amounts of luciferase and pRSVL DNA were present in the host brains for 1 to 2 months. These results have implications for intracerebral viral infections and gene therapy of brain disorders.

Direct gene transfer into nonhuman primate myofibers in vivo

Previously, we showed that rodent muscle has the ability to take up and express plasmid genes injected intramuscularly. This study now demonstrates that nonhuman primate muscle also has this ability to express injected plasmids. A scaled-up version of the standard large preparation of plasmid DNA allowed several tens of milligrams of CCC plasmid DNA to be relatively easily produced and administered to monkeys. After the injection of the E. coli beta-galactosidase reporter gene in pRSVLac-Z, foreign gene expression was localized to both type I and type II myofibers. The luciferase reporter gene in pRSVL was used to quantify the amount of expression. The multiple implantation of plasmid DNA pellets was more efficient in expressing luciferase than the injection of DNA in normal saline. Luciferase activity persisted for at least 4 months after injection. However, the luciferase expression was considerably less than that in rodents. Preliminary studies explored why expression was less in monkeys. Of particular interest was the increased thickness of the perimysium of monkeys as compared to that in rodents. This increased connective tissue may decrease delivery of the plasmid DNA to the myofibers. Anti-nuclear or anti-DNA antibodies were not observed, even after repetitive DNA administrations, and no adverse effects were observed in any of the monkeys.

In vivo regulation of low-density lipoprotein receptor and apolipoprotein B gene expressions by dietary fat and cholesterol in inbred strains of mice

Two proteins that may be important in the hypercholesterolemia and atherosclerosis produced by dietary fat and/or cholesterol are apoB and the LDL-receptor. We evaluated the molecular and genetic regulation of these two proteins by two important components of atherogenic diets: dietary fatty acids and dietary cholesterol. The control diet (C) contained 5% corn oil; the high cholesterol (HC) diets, 5% corn oil plus 0.5% or 2% cholesterol; the high fat diet (HF) 1% corn oil and 20% hydrogenated coconut oil; the fat plus cholesterol diets (HF/C) were the same as HF diet plus either 0.5% or 2% cholesterol. Ten strains of inbred mice were fed the C and HF/C (2% cholesterol) diets. Three strains; C3H, C57BL and SWR, were studied in greater detail. In them the effects of dietary fat and cholesterol were assessed separately and together. These three strains were fed all six diets. Lipoprotein profiles of plasma and indexes of lipoprotein composition were obtained by gel filtration chromatography and in selected strains by gradient ultracentrifugation. Relative rates of transcription of LDL-receptor mRNA and apoB mRNA were measured in purified mouse liver nuclei and levels of LDL-receptor mRNA and apoB mRNA in liver and intestine were quantified by RNA excess solution hybridization assays. The HF/C diet produced rises in plasma total-, VLDL- and LDL-cholesterol and apoB concentrations in the ten strains. VLDL and LDL became cholesterol-enriched and the proportion of total cholesterol transported in VLDL and LDL rose at the expense of HDL. This general pattern of HF/C diet-induced changes was similar in all strains, but there were marked quantitative differences between strains with respect to lipid and lipoprotein concentrations, and compositions and the distribution of cholesterol on both the HC and HF/C diets. The strain-related differences were not due to differences in absorption of dietary cholesterol because, for any given diet, hepatic cholesterol levels increased to the same extent in all strains. Nor were the strain-related differences related to alleles of the apoB gene as determined by RFLP analyses. In the three strains, hepatic LDL-receptor mRNA transcription was suppressed by all diets. But, LDL-receptor mRNA levels in both intestine and liver were suppressed only by the HC and HF/C diets and not by the HF diet. Thus, dietary cholesterol decreased LDL-receptor mRNA levels by mechanisms operating at the transcriptional level, while dietary fatty acids, in addition to inhibiting transcription also appeared to enhance mRNA stability.(ABSTRACT TRUNCATED AT 400 WORDS)

Conditions affecting direct gene transfer into rodent muscle in vivo

This report extends our previous findings that mouse muscle cells in situ can take up naked DNA injected intramuscularly in vivo. Various conditions such as needle type, speed of injection, volume of injection fluid, tonicity of injection fluid, type of solute, type of muscle, physiologic condition of the muscle and age of the animals were appraised for their effect on the levels of luciferase activity expressed from the pRSVL plasmid. Specific conditions such as the use of normal saline as an injection fluid increased the efficiency of expression. The implantation of DNA pellets was an effective way to deliver DNA to muscle, especially for smaller muscle groups. Also, newborn and adult rat muscles expressed plasmid DNA delivered intramuscularly.

Abnormalities of plasma lipoproteins in a new genetically obese rat with non-insulin-dependent diabetes mellitus (Wistar fatty rat)

We investigated plasma lipoprotein profiles and the activities of tissue cholesterol regulating enzymes in Wistar fatty rats, an animal model for non-insulin-dependent diabetes mellitus (NIDDM). Wistar fatty rats were made by transfer of the fa gene to the Wistar Kyoto rats by backcross-breeding. Wistar fatty and control non-diabetic littermates were given a laboratory chow or an atherogenic diet containing 1 percent (weight percent) cholesterol, 0.5 percent cholic acid, and 5 percent lard. Under the chow diet, plasma fasting glucose and immunoreactive insulin concentrations in Wistar fatty rats were 1.5- and 6-fold higher than controls, respectively. Plasma cholesterol was significantly increased in Wistar fatty rats compared with controls. Elevated plasma cholesterol levels in Wistar fatties was accounted for by the increases of cholesterol content in the d less than 1.006 g/ml lipoprotein and high-density lipoproteins. Under the atherogenic diet, plasma cholesterol levels in Wistar fatties were further increased by 129 percent compared with controls. The diet-induced increase of cholesterol contents was shown in all lipoprotein classes for Wistar fatty rats. The activities of regulatory enzymes for cholesterol biosynthesis or absorption were measured in Wistar fatty rats. Both hepatic and intestinal 3-hydroxy-3-methylglutaryl (HMG)-CoA reductase activities were significantly higher in Wistar fatty rats than those in controls (P less than 0.05 and P less than 0.01, respectively). ACAT activities in Wistar fatties were significantly increased in the intestine (P less than 0.05) and decreased in the liver in comparison with controls (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Editing of apolipoprotein B messenger RNA in differentiated Caco-2 cells

During the differentiation of human enterocytes, the secretion of apolipoprotein B is switched from the apoB-100 form seen almost exclusively in fetal cells to the apoB-48 form seen almost exclusively in adult cells. This switch is accomplished by the post-transcriptional editing of the messenger RNA for apoB-100. We report that a similar switch occurs during the differentiation of the human colonic carcinoma cell line, Caco-2, and that this is accomplished by the same mRNA editing mechanism. Caco-2 cells cultured on Millipore filters developed confluent electrically resistant monolayers, and on Western blot analysis, using a monoclonal antibody directed against the amino terminal region of human apoB-100 (Mab C1.4), secreted greater than 50% apoB-48 (of total apoB-100) into culture media, while Caco-2 cells grown on plastic secreted greater than 95% apoB-100. To assess whether mRNA editing was responsible for the switchover from apoB-100 to apoB-48, apoB cDNA fragments spanning nucleotides 6504-6784 of apoB mRNA were synthesized using RNA isolated from Caco-2 cells grown on filters and Caco-2 cells grown on plastic. The appropriate oligonucleotide primers and Moloney murine leukemia virus reverse transcriptase were used. The resulting cDNA fragments were amplified by the polymerase chain reaction (PCR), and PCR products were subcloned and sequenced. A single cytosine/thymine base change occurred in 8/20 clones of cDNA derived from Caco-2 cells grown on filters (corresponding to a cytosine/uridine change in mRNA) and in 1/25 clones of cDNA derived from Caco-2 cells grown on plastic. PCR products of genomic sequences from Caco-2 cells did not contain the stop codon.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic heterogeneity of plasma lipoproteins in the mouse: control of low density lipoprotein particle sizes by genetic factors

In order to assess the genetic control of sizes and concentrations of mouse plasma low density (LDL) and high density lipoproteins (HDL), we used gel permeation fast protein liquid chromatography (FPLC) and nondenaturing gradient polyacrylamide gel electrophoresis to measure the particle sizes of LDL and HDL. Using chromatography we also quantified LDL-cholesterol and HDL-cholesterol concentrations in plasma and used them as indexes of plasma concentrations of the respective particles among 10 inbred strains (AKR/J, BALB/cByJ, C3H/HeJ, C57BL/6J, C57BL/6ByJ, C57L/J, DBA/1LacJ, 129/J, NZB/BINJ, SWR/J) and three sets of recombinant inbred (RI) strains (AKXL/TyJ, BXH/TyJ, CXB/ByJ) of mice. HDL had a dichotomous distribution among the 10 inbred strains. One group had large HDL particle sizes and high HDL-cholesterol concentrations. Another group had smaller HDL particles and lower HDL-cholesterol concentrations, and HDL sizes and HDL-cholesterol concentrations were significantly correlated. In the RI strains, HDL sizes and HDL-cholesterol cholesterol concentrations clearly segregated with one or another of the progenitor strains, and RI strain distributions showed a strong linkage to the apolipoprotein (apo) A-II gene (Apoa-2). In contrast, LDL-cholesterol concentrations and particle sizes on FPLC did not show dichotomous distributions among the 10 inbred strains. In RI strains, the configuration of the LDL FPLC profiles and LDL-cholesterol concentrations did resemble one or another of the progenitors in the majority of cases, but LDLs of several RI strains resembled neither progenitor strain in profile configuration, and LDL-cholesterol concentrations were both greater and smaller than those of progenitor strains. However, LDL particle diameters (as judged by peaks of LDL-cholesterol profiles) did segregate with progenitors in 29/33 (88%) of RI strains suggesting that a major gene may affect LDL size. In attempting to identify a major LDL-size determining gene, we compared apoB gene restriction fragment length polymorphisms (RFLPs) to the distributions of peak LDL sizes in RI strains. Concordance rates of peak LDL sizes to apoB gene polymorphisms were 18/22 (82%) for the EcoRV RFLP, 5/7 (71%) for HindIII RFLP, and 23/29 (79%) for both (range of P values 0.90-0.95). Thus we could not unequivocally implicate the apoB gene in determining the size of LDL particles. In summary, the genetic control of LDL sizes is more complicated than is the case for HDL; however, the differences in LDL size among these strains of mice may be controlled by a major, as yet unidentified, gene.

Genetic heterogeneity of lipoproteins in inbred strains of mice: analysis by gel-permeation chromatography

To assess genetic variation of murine lipoprotein profiles, plasma lipoproteins of 11 inbred strains, AKR/J, BALB/cByJ, C3H/HeJ, C57BL/6J, C57BL/6ByJ, C57L/J, DBA/1LacJ, 129/J, NZB/B1NJ, PL/J, and SWR/J, were analyzed by gel-permeation chromatography (fast peptide liquid chromatography) and nondenaturing gradient gel electrophoresis. Vena caval blood was drawn after 18 to 20 hours of fasting. Plasma triglyceride and cholesterol concentrations ranged from 12.9 mg/dL (C57BL/6ByJ) to 66.9 mg/dL (C3H/HeJ) and from 54.8 mg/dL (AKR/J) to 128.5 mg/dL (NZB/B1NJ), respectively. Mouse strain-related heterogeneities of very low-, low-, and high-density lipoprotein (VLDL, LDL, and HDL, respectively) concentrations were documented; VLDL-triglyceride concentrations ranged from 7.5 mg/dL to 38.8 mg/dL, LDL cholesterol from 12.0 mg/dL to 39.6 mg/dL, and HDL cholesterol from 41.3 mg/dL to 92.4 mg/dL. Hyper-VLDL-triglyceridemia was present in C3H/HeJ and SWR/J strains and hyper-LDL-cholesterolemia in NZB/B1NJ, C3H/HeJ, and DBA/1LacJ. VLDL cholesterol/VLDL triglyceride ratios also ranged widely among strains (0.13 to 0.43), with C57BL/6J, C57BL/6ByJ, and C57L/J, the strains particularly susceptible to diet-induced atherosclerosis, having the highest VLDL-lipid ratio. LDL and HDL size heterogeneities were also observed. LDL and HDL diameters ranged between 24.1 nm and 29.4 nm, and between 9.24 nm and 10.32 nm, respectively. Although LDL sizes showed no segregation, HDL sizes fell into two groups. C57L/J and C57BL/6J possessed low HDL-cholesterol concentrations and small-sized HDL. HDL sizes were positively correlated with HDL-cholesterol concentrations (r = .90, P less than .001) and LDL-cholesterol concentrations (r = .85, P less than .001), but LDL sizes did not correlate with lipoprotein concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Physical, achievement and personality characteristics of Chinese children

The physical, achievement, and personality characteristics of Chinese schoolchildren are evaluated. The results of two surveys of Chinese schoolchildren, conducted in Beijing and Jilin Province, are presented. In the Beijing sample, the differences between only children and others were small but statistically significant, with the only children having higher scores in achievement and physical size. In the Jilin Province sample, the differences between only children and others were also small but significant. These differences were found entirely in physical characteristics, with only children being smaller, perhaps because the only children in the Jilin sample were much younger than the non-only children. Analyses of the combined sample of Beijing and Jilin schoolchildren indicated that the only-child advantages in achievement were found among children from urban families, not rural peasant families. While significant differences in height and weight were found in all three samples, none of the results indicated a significant difference in the proportion of body fat. None of the analyses indicated that only children had undesirable personalities, as judged by teachers and mothers.

Relationship between hypertriglyceridemia and uric acid production in primary gout

The relationship between uric acid metabolism and lipid levels was analyzed in 148 male subjects with primary gout. The subjects were divided into three groups according to their alcohol consumption: heavy drinkers, moderate drinkers, and nondrinkers or mild drinkers. There was no correlation between urinary uric acid excretion and serum triglyceride (TG) levels in the heavy group, but a marginally significant correlation was shown in the moderate group (P less than .05), and a significant correlation was observed in the nondrinker or mild group (P less than .001). This relationship in the nondrinker or mild group was also found to be significant after adjustment for BMI and age by multiple regression analysis. Serum lipoproteins were analyzed by sequential preparative ultracentrifugation in 21 patients with primary gout who neither drank alcohol nor were obese; VLDL-TG level, but not the VLDL cholesterol level, was found to be significantly correlated with 24-hour urinary uric acid excretion. These results indicate that there is a close correlation between the degree of uric acid production, as judged by 24-hour urinary uric acid excretion, and lipoprotein TG metabolism when the influence of alcohol intake is excluded.

Decreased activity of acyl-CoA:cholesterol acyltransferase by insulin in human intestinal cell line Caco-2

Diabetes mellitus is accompanied by increased intestinal cholesterol synthesis and cholesterol esterification. Both are reversed by insulin therapy. To assess whether the action of insulin on cholesterol esterification by intestinal cells is direct or mediated by other effectors associated with diabetes, we investigated the effect of insulin on the activity of microsomal acyl-CoA:cholesterol acyltransferase (ACAT) and on the incorporation rate of [14C]oleic acid into cholesteryl oleate in the Caco-2 human intestinal cell line. Microsomal ACAT activity of cells that were incubated with insulin for 3 h at a concentration of 1, 10, and 100 microU/ml was decreased by 48, 58, and 74%, respectively, compared with cells cultured in insulinfree medium. This effect was evident as soon as 10 min after the addition of 10 microU/ml insulin. The inhibition by insulin was reversible. After incubation for 24 h, intracellular esterified-cholesterol content and the ratio of esterified to nonesterified cholesterol were significantly lower in the cells treated with insulin (100 microU/ml) than in those not treated with insulin (esterified cholesterol 48.6 +/- 2.0 vs. 74.2 +/- 4.3 nmol/mg protein, respectively, P less than .005; esterified to nonesterified ratio 0.280 +/- 0.008 vs. 0.359 +/- 0.059, respectively, P less than .05). Cells cultured on filters manifested physiologic polarity; greater than 90% of [14C]oleic acid-labeled cholesterol ester secreted by cells was secreted into the basolateral chambers. Incorporation of [14C]oleic acid into cholesteryl oleate over 24 h in the cells and in the medium of the basolateral chamber was suppressed by 100 microU/ml insulin by 23 and 40%, respectively. These findings indicate that insulin acts directly on the enterocytes to suppress intestinal cholesterol ester synthesis and secretion.

Cholesterol-lowering effect of N-(alpha-methylbenzyl)linoleamide (melinamide) in cholesterol-fed diabetic rats

Cholesterol loading of diabetic rats is known to induce marked hyperlipoproteinaemia, and we have reported that enhancement of the activity of intestinal acyl-CoA:cholesterol acyltransferase (ACAT), one of the key enzymes involved in cholesterol absorption, might play an important role in the development of hypercholesterolaemia in these animals. In the present study, we have shown that treatment with N-(alpha-methylbenzyl)linoleamide (melinamide), a new hypocholesterolaemic drug, caused a substantial decrease of the enhanced intestinal ACAT activity in diabetic rats, but did not affect intestinal cholesterol esterase activity. Furthermore, marked improvement of hypercholesterolaemia in cholesterol-fed diabetic rats occurred concomitantly with the drug treatment. These results suggest that intestinal ACAT activity is closely related to the serum cholesterol level in diabetic rats, and show that melinamide lowers intestinal ACAT activity.

Increased activity of intestinal acyl-CoA: cholesterol acyltransferase in rats with streptozocin-induced diabetes and restoration by insulin supplementation

We examined the activities of intestinal acyl-CoA:cholesterol acyltransferase (ACAT) and cholesterol esterase, enzymes regulating cholesterol absorption, in rats with streptozocin-induced diabetes (STZ-D) to clarify the effect of diabetes on cholesterol absorption. Three weeks after the induction of diabetes, plasma cholesterol levels were slightly but significantly increased in diabetic rats compared with control animals, whereas a far more remarkable increase in plasma cholesterol was observed in diabetic rats when fed an atherogenic diet containing 1% cholesterol, 0.5% cholic acid, and 5% lard. Microsomal ACAT activity in intestinal mucosa was three times higher in diabetic than in control rats. However, no significant difference in the enzyme activity could be detected between diabetic animals fed control chow and those fed the atherogenic diet. Furthermore, insulin supplementation given to diabetic rats caused a reduction of enzyme activity to the levels found in control animals. In contrast, cholesterol esterase activity in rat intestinal mucosa was unaffected by either the induction of diabetes or the atherogenic diet feeding. In conclusion, we disclosed that apparent ACAT activity in intestinal mucosa is elevated in STZ-D rats. Therefore, we postulate that enhancement of CoA-dependent cholesterol esterification in the intestine might be one of the major factors responsible for hypercholesterolemia in diabetes.

Influence of endogenous hyperinsulinism on high density lipoprotein2 level in type 2 (non-insulin-dependent) diabetes mellitus and impaired glucose tolerance

We determined the insulin response to an oral glucose ingestion and levels of serum lipoproteins in 25 untreated patients with type 2 diabetes mellitus, in 26 subjects with impaired glucose tolerance (IGT), and in 35 non-diabetic control subjects. The three groups had similar compositions with respect to age and sex distribution. The levels of VLDL triglyceride in the subjects with type 2 diabetes or IGT were higher than those in controls. Serum HDL- and HDL2 cholesterol were significantly decreased in type 2 diabetics, and the subjects with IGT showed a similar tendency. Serum apolipoprotein A-II levels were lower in the male subjects with type 2 diabetes or IGT than in controls. Insulin response, i.e., sum of immunoreactive insulin (IRI) levels at basal, 30, 60, 90 and 120 min after a 75-g oral glucose load, negatively correlated to HDL- and HDL2 cholesterol levels (r = -0.396, P less than 0.05; r = -0.482, P less than 0.001, respectively), and positively correlated to VLDL triglyceride values (r = 0.485, P less than 0.001) in the male subjects with type 2 diabetes or IGT. In the female subjects, fasting plasma IRI values significantly correlated to HDL cholesterol (r = -0.496, P less than 0.05). There was a significant negative correlation between the concentrations of HDL2 cholesterol and VLDL triglyceride. These data show that lipoprotein metabolism, not only in type 2 diabetics, but also in IGT tends to show changes such as decreased HDL2 cholesterol and increased VLDL triglyceride levels, and which might be related to the hypersecretion of endogenous insulin.